Solenoid



Patented Dec. 5, 1939 UNITED STATES PATENT OFFICE soLENom Charles N. Weiler, Nahant, Mass., assignor to a.

General Electric Company, a corporation of New York Application August 14, 1937, ySerial No. 159,120

1 Claim. (Cl. 175-341) My invention relates to solenoids, and more iron core, and when so raised, it nrst moves particularly to a means for steadying the operaabove its ultimate position, and then moves tion of the movingarmature within the solenoid. through several oscillations above and below this One object of my invention is to provide a position before it finally stops. These oscillabraking action in the solenoid so that upon actions are objectionable in an application of this 5 tuation, the armature will glide to its end posisort, for the reason that it is possible for the tion and stay at that position without oscillation. armature to oscillate suiclently for the pawl to For a better understanding of my invention engage an extra tooth on the ratchet wheel, and together with other and further objects thereof, thereby move the drum farther than is intended reference is had to the following description taken for a single energization of the solenoid coil. 10 in connection with the accompanying drawing, In accordance with my invention, these oscillaand its scope will be pointed out in the appended tory movements are eliminated by providing a claim. magnetic brake which becomes automatically ef- In the accompanying drawing, Fig. 1 illustrates fective at the end of the movement, or stroke,

16 a solenoid built in accordance with my invention of the armature and causes it to slide into its 15 applied to a, switch-drum ratchet mechanism; nal position and stay there until the armature Fig. 2 is a cross-sectional elevation through the is deenergized. In Order t0 Carry Out my invencenter of the coil; Fig. 3 is a front elevation of tion in the simplest manner. I mOdfy the COIe a core lamination; Fig. 4 is a cross-sectional view of the solenoid so that the moving armature may zo looking in the direction of arrows 4-4 of Fig. contact the stationary core during a part of its 20 2; and Fig. 5 is a perspective view of the armatravel and by magnetic attraction encounter sufture guide sleeve used within the S01en0id, Vicient friction to cause it to glide to its ultimate Referring to the drawing in detail, Fig. 1 disposition and stop without rebound. closes a solenoid comprising a coil 5, a closed One embodiment of my invention iS illustrated g5 type of core 6, and an armature 1 m0vab1e in Figs. 2 and 3. Fig. 2 illustrates a cross-sec- 25 through the coil in a guide sleeve 8. When the tional elevation of a closed type of core which is coil 5 is energized, the armature moves into the built up of two bundles of laminations shaped position illustrated in Fig. 2, and when the coil as illustrated in Fig. 3. The lamination illusis deenergized, it drops into the position shown trailed in Fig. 3 comprises tWO hOl'ZOIltal legs 20 in Fig. 1. and 2I connected by a vertical leg 22. The bun- 30 In Fig. l, a solenoid is illustrated as being dles are arranged opposite to each other and used to rotate, step-by-step, a switch operating spaced by end pieces 23 and 24. so as to provide, drum comprising a shaft I0, a series of disks II, room for the armature 1 between the ends of the and a ratchet wheel I2, the shaft I0 being mounthorizontal legs. The end pieces 23 are arranged ed for rotation in a pair of lugs I3, of which only on opposite sides at the bottom of the core, and 35 one is illustrated. A ratchet arm I4 carrying the end pieces 24 are arranged on opposite sides a pawl I5 is mounted for rotation on the shaft at the top of the core, the rivets 9 project through III by its sleeve I6. The arm I4 is pivoted to the laminations and end pieces and form a solid the end of the armature 'I by a pin I1; An upstructure. The end pieces 24 are provided with 40 ward movement of the armature, therefore, rotabs 25 by means of which the core may be sup- 0 tates the arm I4 clockwise as viewed from the ported. In Fig. 1, for example, the core is pivleft, Fig. 1, and permits the pawl I5 to slide over otally supported from a lug 26 by a pin 21, prothe teeth on the ratchet wheel, the pawl being jecting through the lug and the tabs 25, so as held in contact with the ratchet wheel by a `to permit the necessary lateral movement of the spring I8. When the armature drops due tov lower end of the armature, during the arcuate 45 the deenergization of the coil, the pawl engages movement of the ratchet arm I4.

a tooth and advances the drum counterclockwise. As pointed out above, the armature 'I is guid- In applications of the type above described, ed by a non-magnetic sleeve 8 which projects it is desirable to have the armature move to through the coil and between pairs of opposite its upper position in one continuous movement, legs of the core laminatlons. In order to pro- 50 and stop at that position without rebound or vide a magnetic brake in accordance with my other oscillatory movements. In solenoids of invention, I mount the nonmagnetic sleeve so the type disclosed, however, the movement is that its upper end projects only partially besuch that the armature is raised to a central or tween the end surfaces of the upper horizontal intermediate position between the arms of the legs of the core and I further provide the upper leg of the one bundle of the laminations with projections 28. 'I'he projection 28 is somewhat longer than the thickness of the metal in the sleeve 8, so that the end surface thereof projects slightly into the sleeve. When the laminations are assembled, these projections form a wall which projects across the full width of the sleeve, and has a length which is approximately equal to one-half of the core leg width. When the armature moves upwardly due to the energization of the coil, it is attracted toward this exposed and projecting portion of the core and slides over the surface of it, encounteringv considerable friction during such movement. The amount of this friction is regulated by the area of the surface of the projections and depends further upon the intensity of the magnetic iiux.

A length of surface equal to one-half of the core leg end surface is found to be suicient to permit the armature 'l to glide to its ultimate position without overshooting this position.

Fig. 4 is a horizontal sectional view through the core 6 and the coil 5, indicating the relative position of the sleeve and the armature, and Fig. 5 discloses the sleeve 8 which is made of a non-magnetic material such as brass, and is provided with a tab 29 by means of which it is attached to the end plate 23 of the core by means of a screw 30.

What I claim as new and desire to secure by Letters Patent of the United States is:

In combination, a solenoid coil, a magnetic core surrounding said coil and comprising vertical legs adjacent the outer surface of said coil and horizontal legs integral with said vertical legs respectively and projecting towards each other along the ends of said coil, the ends of said horizontal legs being spaced from each other to receive an armature, a non-magnetic sleeve extending through said coil transverse of the lower horizontal legs of said core and partly transverse of the upper horizontal legs of said core, an armature movable axially into said coil upon the energization thereof into an upper position wherein the upper end of said armature substantially iills the space between the ends of said upper horizontal legs and a projection on one of said horizontal legs extending over the end of said sleeve and having an end surface substantially ilush with the inner surface of said sleeve whereby said armature when moving to its upper position is attracted and frictionally retarded by said magnetic projection for only a portion of its upward movement and only at the end of its stroke.

CHARLES N. WEILER.4 

